Method and apparatus for the treatment of a material web and for control of the behavior of a material web

Abstract

The solution of the invention relates to a method and apparatus for the treatment of a paper web in a paper or cardboard machine. The essential feature of the solution of the invention is that a moving material web ( 1 ), its properties and/or its behavior are influenced by the use of a gas ( 2 ) by causing the gas ( 2 ) to flow substantially toward the material web or to its immediate vicinity.

What is claimed is:  
     
       1. A method for treating a moving web and facilitating the transfer of the web between spaced successive rolls in a paper making machine wherein the web is unsupported between at least two successive rolls, the method comprising the steps of: 
       a) sensing at least one of ( 1 ) the motion of the web, ( 2 ) the tension of the web, ( 3 ) the moisture content of the web and ( 4 ) air pressure levels above and below the web;  
       b) introducing a flow of a gas onto the surface of the upstream one of the successive rolls at a location where separation of the web from the roll is intended to occur; and  
       c) controlling, in response to the sensing performed in step a), at least one of ( 1 ) the direction of the gas flow, ( 2 ) the pressure of the gas, ( 3 ) the composition of the gas, ( 4 ) the humidity of the gas and ( 5 ) the temperature of the gas,  
       said flow of a gas comprising a plurality of gas flows that are spaced from each other in a direction transverse to the movement of the web from roll to roll, and said controlling performed in step c) applying to each of the gas flows individually.  
     
     
       2. Apparatus for treating a moving web and facilitating the transfer of the web between spaced successive rolls in a paper making machine wherein the web is unsupported between at least two successive rolls, the apparatus comprising: 
       at least one sensor for sensing at least one of ( 1 ) the motion of the web, ( 2 ) the tension of the web, ( 3 ) the moisture content of the web and ( 4 ) air pressure levels above and below the web;  
       means for introducing a flow of a gas onto the surface of the upstream one of the successive rolls at a location where separation of the web from the roll is intended to occur; and  
       means for controlling, in response to the sensing performed in step a), at least one of ( 1 ) the direction of the gas flow, ( 2 ) the pressure of the gas, ( 3 ) the composition of the gas, ( 4 ) the humidity of the gas and ( 5 ) the temperature of the gas,  
       wherein said means for introducing a flow of gas comprises a conduit with apertures that are spaced from each other in a direction transverse to the movement of the web from roll to roll, thus providing the flow of gas with a plurality of gas flows, and  
       wherein the means for controlling controls each of the plurality of gas flows individually.